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11#include <linux/clockchips.h>
12#include <linux/kernel.h>
13#include <linux/mutex.h>
14#include <linux/sched.h>
15#include <linux/notifier.h>
16#include <linux/pm_qos.h>
17#include <linux/cpu.h>
18#include <linux/cpuidle.h>
19#include <linux/ktime.h>
20#include <linux/hrtimer.h>
21#include <linux/module.h>
22#include <linux/suspend.h>
23#include <linux/tick.h>
24#include <trace/events/power.h>
25
26#include "cpuidle.h"
27
28DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
29DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
30
31DEFINE_MUTEX(cpuidle_lock);
32LIST_HEAD(cpuidle_detected_devices);
33
34static int enabled_devices;
35static int off __read_mostly;
36static int initialized __read_mostly;
37
38int cpuidle_disabled(void)
39{
40 return off;
41}
42void disable_cpuidle(void)
43{
44 off = 1;
45}
46
47bool cpuidle_not_available(struct cpuidle_driver *drv,
48 struct cpuidle_device *dev)
49{
50 return off || !initialized || !drv || !dev || !dev->enabled;
51}
52
53
54
55
56
57
58int cpuidle_play_dead(void)
59{
60 struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
61 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
62 int i;
63
64 if (!drv)
65 return -ENODEV;
66
67
68 for (i = drv->state_count - 1; i >= 0; i--)
69 if (drv->states[i].enter_dead)
70 return drv->states[i].enter_dead(dev, i);
71
72 return -ENODEV;
73}
74
75static int find_deepest_state(struct cpuidle_driver *drv,
76 struct cpuidle_device *dev,
77 unsigned int max_latency,
78 unsigned int forbidden_flags,
79 bool freeze)
80{
81 unsigned int latency_req = 0;
82 int i, ret = 0;
83
84 for (i = 1; i < drv->state_count; i++) {
85 struct cpuidle_state *s = &drv->states[i];
86 struct cpuidle_state_usage *su = &dev->states_usage[i];
87
88 if (s->disabled || su->disable || s->exit_latency <= latency_req
89 || s->exit_latency > max_latency
90 || (s->flags & forbidden_flags)
91 || (freeze && !s->enter_freeze))
92 continue;
93
94 latency_req = s->exit_latency;
95 ret = i;
96 }
97 return ret;
98}
99
100#ifdef CONFIG_SUSPEND
101
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104
105
106int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
107 struct cpuidle_device *dev)
108{
109 return find_deepest_state(drv, dev, UINT_MAX, 0, false);
110}
111
112static void enter_freeze_proper(struct cpuidle_driver *drv,
113 struct cpuidle_device *dev, int index)
114{
115
116
117
118
119
120 RCU_NONIDLE(tick_freeze());
121
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125
126 stop_critical_timings();
127 drv->states[index].enter_freeze(dev, drv, index);
128 WARN_ON(!irqs_disabled());
129
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133
134 RCU_NONIDLE(tick_unfreeze());
135 start_critical_timings();
136}
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145
146int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev)
147{
148 int index;
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154
155 index = find_deepest_state(drv, dev, UINT_MAX, 0, true);
156 if (index > 0)
157 enter_freeze_proper(drv, dev, index);
158
159 return index;
160}
161#endif
162
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167
168
169int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
170 int index)
171{
172 int entered_state;
173
174 struct cpuidle_state *target_state = &drv->states[index];
175 bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
176 ktime_t time_start, time_end;
177 s64 diff;
178
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182
183
184 if (broadcast && tick_broadcast_enter()) {
185 index = find_deepest_state(drv, dev, target_state->exit_latency,
186 CPUIDLE_FLAG_TIMER_STOP, false);
187 if (index < 0) {
188 default_idle_call();
189 return -EBUSY;
190 }
191 target_state = &drv->states[index];
192 }
193
194
195 sched_idle_set_state(target_state);
196
197 trace_cpu_idle_rcuidle(index, dev->cpu);
198 time_start = ktime_get();
199
200 stop_critical_timings();
201 entered_state = target_state->enter(dev, drv, index);
202 start_critical_timings();
203
204 time_end = ktime_get();
205 trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
206
207
208 sched_idle_set_state(NULL);
209
210 if (broadcast) {
211 if (WARN_ON_ONCE(!irqs_disabled()))
212 local_irq_disable();
213
214 tick_broadcast_exit();
215 }
216
217 if (!cpuidle_state_is_coupled(drv, entered_state))
218 local_irq_enable();
219
220 diff = ktime_to_us(ktime_sub(time_end, time_start));
221 if (diff > INT_MAX)
222 diff = INT_MAX;
223
224 dev->last_residency = (int) diff;
225
226 if (entered_state >= 0) {
227
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230
231 dev->states_usage[entered_state].time += dev->last_residency;
232 dev->states_usage[entered_state].usage++;
233 } else {
234 dev->last_residency = 0;
235 }
236
237 return entered_state;
238}
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248int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
249{
250 return cpuidle_curr_governor->select(drv, dev);
251}
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262
263int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
264 int index)
265{
266 if (cpuidle_state_is_coupled(drv, index))
267 return cpuidle_enter_state_coupled(dev, drv, index);
268 return cpuidle_enter_state(dev, drv, index);
269}
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279void cpuidle_reflect(struct cpuidle_device *dev, int index)
280{
281 if (cpuidle_curr_governor->reflect && index >= 0)
282 cpuidle_curr_governor->reflect(dev, index);
283}
284
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287
288void cpuidle_install_idle_handler(void)
289{
290 if (enabled_devices) {
291
292 smp_wmb();
293 initialized = 1;
294 }
295}
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298
299
300void cpuidle_uninstall_idle_handler(void)
301{
302 if (enabled_devices) {
303 initialized = 0;
304 wake_up_all_idle_cpus();
305 }
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311 synchronize_rcu();
312}
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317void cpuidle_pause_and_lock(void)
318{
319 mutex_lock(&cpuidle_lock);
320 cpuidle_uninstall_idle_handler();
321}
322
323EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
324
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328void cpuidle_resume_and_unlock(void)
329{
330 cpuidle_install_idle_handler();
331 mutex_unlock(&cpuidle_lock);
332}
333
334EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
335
336
337void cpuidle_pause(void)
338{
339 mutex_lock(&cpuidle_lock);
340 cpuidle_uninstall_idle_handler();
341 mutex_unlock(&cpuidle_lock);
342}
343
344
345void cpuidle_resume(void)
346{
347 mutex_lock(&cpuidle_lock);
348 cpuidle_install_idle_handler();
349 mutex_unlock(&cpuidle_lock);
350}
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359int cpuidle_enable_device(struct cpuidle_device *dev)
360{
361 int ret;
362 struct cpuidle_driver *drv;
363
364 if (!dev)
365 return -EINVAL;
366
367 if (dev->enabled)
368 return 0;
369
370 drv = cpuidle_get_cpu_driver(dev);
371
372 if (!drv || !cpuidle_curr_governor)
373 return -EIO;
374
375 if (!dev->registered)
376 return -EINVAL;
377
378 ret = cpuidle_add_device_sysfs(dev);
379 if (ret)
380 return ret;
381
382 if (cpuidle_curr_governor->enable &&
383 (ret = cpuidle_curr_governor->enable(drv, dev)))
384 goto fail_sysfs;
385
386 smp_wmb();
387
388 dev->enabled = 1;
389
390 enabled_devices++;
391 return 0;
392
393fail_sysfs:
394 cpuidle_remove_device_sysfs(dev);
395
396 return ret;
397}
398
399EXPORT_SYMBOL_GPL(cpuidle_enable_device);
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407
408void cpuidle_disable_device(struct cpuidle_device *dev)
409{
410 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
411
412 if (!dev || !dev->enabled)
413 return;
414
415 if (!drv || !cpuidle_curr_governor)
416 return;
417
418 dev->enabled = 0;
419
420 if (cpuidle_curr_governor->disable)
421 cpuidle_curr_governor->disable(drv, dev);
422
423 cpuidle_remove_device_sysfs(dev);
424 enabled_devices--;
425}
426
427EXPORT_SYMBOL_GPL(cpuidle_disable_device);
428
429static void __cpuidle_unregister_device(struct cpuidle_device *dev)
430{
431 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
432
433 list_del(&dev->device_list);
434 per_cpu(cpuidle_devices, dev->cpu) = NULL;
435 module_put(drv->owner);
436}
437
438static void __cpuidle_device_init(struct cpuidle_device *dev)
439{
440 memset(dev->states_usage, 0, sizeof(dev->states_usage));
441 dev->last_residency = 0;
442}
443
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449
450
451static int __cpuidle_register_device(struct cpuidle_device *dev)
452{
453 int ret;
454 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
455
456 if (!try_module_get(drv->owner))
457 return -EINVAL;
458
459 per_cpu(cpuidle_devices, dev->cpu) = dev;
460 list_add(&dev->device_list, &cpuidle_detected_devices);
461
462 ret = cpuidle_coupled_register_device(dev);
463 if (ret)
464 __cpuidle_unregister_device(dev);
465 else
466 dev->registered = 1;
467
468 return ret;
469}
470
471
472
473
474
475int cpuidle_register_device(struct cpuidle_device *dev)
476{
477 int ret = -EBUSY;
478
479 if (!dev)
480 return -EINVAL;
481
482 mutex_lock(&cpuidle_lock);
483
484 if (dev->registered)
485 goto out_unlock;
486
487 __cpuidle_device_init(dev);
488
489 ret = __cpuidle_register_device(dev);
490 if (ret)
491 goto out_unlock;
492
493 ret = cpuidle_add_sysfs(dev);
494 if (ret)
495 goto out_unregister;
496
497 ret = cpuidle_enable_device(dev);
498 if (ret)
499 goto out_sysfs;
500
501 cpuidle_install_idle_handler();
502
503out_unlock:
504 mutex_unlock(&cpuidle_lock);
505
506 return ret;
507
508out_sysfs:
509 cpuidle_remove_sysfs(dev);
510out_unregister:
511 __cpuidle_unregister_device(dev);
512 goto out_unlock;
513}
514
515EXPORT_SYMBOL_GPL(cpuidle_register_device);
516
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519
520
521void cpuidle_unregister_device(struct cpuidle_device *dev)
522{
523 if (!dev || dev->registered == 0)
524 return;
525
526 cpuidle_pause_and_lock();
527
528 cpuidle_disable_device(dev);
529
530 cpuidle_remove_sysfs(dev);
531
532 __cpuidle_unregister_device(dev);
533
534 cpuidle_coupled_unregister_device(dev);
535
536 cpuidle_resume_and_unlock();
537}
538
539EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
540
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546
547
548void cpuidle_unregister(struct cpuidle_driver *drv)
549{
550 int cpu;
551 struct cpuidle_device *device;
552
553 for_each_cpu(cpu, drv->cpumask) {
554 device = &per_cpu(cpuidle_dev, cpu);
555 cpuidle_unregister_device(device);
556 }
557
558 cpuidle_unregister_driver(drv);
559}
560EXPORT_SYMBOL_GPL(cpuidle_unregister);
561
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572
573int cpuidle_register(struct cpuidle_driver *drv,
574 const struct cpumask *const coupled_cpus)
575{
576 int ret, cpu;
577 struct cpuidle_device *device;
578
579 ret = cpuidle_register_driver(drv);
580 if (ret) {
581 pr_err("failed to register cpuidle driver\n");
582 return ret;
583 }
584
585 for_each_cpu(cpu, drv->cpumask) {
586 device = &per_cpu(cpuidle_dev, cpu);
587 device->cpu = cpu;
588
589#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
590
591
592
593
594
595 if (coupled_cpus)
596 device->coupled_cpus = *coupled_cpus;
597#endif
598 ret = cpuidle_register_device(device);
599 if (!ret)
600 continue;
601
602 pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
603
604 cpuidle_unregister(drv);
605 break;
606 }
607
608 return ret;
609}
610EXPORT_SYMBOL_GPL(cpuidle_register);
611
612#ifdef CONFIG_SMP
613
614
615
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617
618
619
620static int cpuidle_latency_notify(struct notifier_block *b,
621 unsigned long l, void *v)
622{
623 wake_up_all_idle_cpus();
624 return NOTIFY_OK;
625}
626
627static struct notifier_block cpuidle_latency_notifier = {
628 .notifier_call = cpuidle_latency_notify,
629};
630
631static inline void latency_notifier_init(struct notifier_block *n)
632{
633 pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
634}
635
636#else
637
638#define latency_notifier_init(x) do { } while (0)
639
640#endif
641
642
643
644
645static int __init cpuidle_init(void)
646{
647 int ret;
648
649 if (cpuidle_disabled())
650 return -ENODEV;
651
652 ret = cpuidle_add_interface(cpu_subsys.dev_root);
653 if (ret)
654 return ret;
655
656 latency_notifier_init(&cpuidle_latency_notifier);
657
658 return 0;
659}
660
661module_param(off, int, 0444);
662core_initcall(cpuidle_init);
663